asp.net mvc - MVC HandleError filter didn't catch an exception

Question

I've an MVC 3 web app in which I'm using "HandleError" Action Filter for exception handling. I've this action filter implemented as follows:

[HandleError]
public class BaseController : Controller {...}

This is the base class from which all of my controllers are derived. In my web.config I've and there's an Error.cshtml in my Shared folder (.cshtml because I use Razor). Everything has been working fine and I get a fine exception handling (formatted by my function)

Recently, somehow I got and "unhandled exception (YSOD)" and because of "customErrors" I got the default ASP.Net error message which didn't have any info about the actual exception. This happened in an AJAX post back. However, I'm unable to reproduce it.

Is it possible for any sort of errors to escape this action filter?

Answer 1

Is it possible for any sort of errors to escape this action filter?

HandleError filter doesn't catch all the exceptions fired in an application. It can capture exceptions that are fired inside actions, action filters.. simply inside the MVC context. Also it doesn't capture HTTP exceptions having status code other than 500. Relying only on HandleError filter in an MVC application is a bad idea.

You should still rely on the Application_Error event to do some logging and customErrors section to display a custom error page for the exceptions that are not captured by HandleError.

I've written a blog post on this subject that may help you.